show Abstracthide AbstractMountain lions (Puma concolor) were previously endemic across the Northeastern United States. The species was officially declared regionally extinct in 2011 by the U.S. Fish and Wildlife Service, although the Northeastern population of P. concolor has been almost nonexistent since the early 1800s, likely as a consequence of targeted predator hunting by farmers to protect livestock, combined with historical habitat loss and fragmentation. The last documented observation of P. concolor in Pennsylvania specifically was in 1874, and the last time (prior to recent long-distance migration events) that a mountain lion was observed east of the Mississippi River and north of Florida was 1938 in Maine. This regionally extinct mountain lion is Pennsylvania State University’s official mascot as the ‘Nittany Lion’. Our goal in this study was to use recent methodological advances in ancient DNA and massively parallel sequencing to reconstruct the complete mitochondrial DNA (mtDNA) genomes of multiple Pennsylvania Nittany Lion individuals from samples collected from their preserved skins. This effort is the initial stage of a broader Nittany Lion Genome project intended to involve Penn State undergraduate students in ancient DNA and bioinformatics research and to engage the broader Penn State community in discussions about conservation biology and extinction. Complete mtDNA genome sequences were obtained from five Nittany Lion individuals. We compared these sequences to previously published mtDNA data for P. concolor individuals from the Western U.S. and Florida in order to begin to estimate how much genetic diversity was lost with the regional extinction and to update knowledge of genetic relationships among the different regional populations.